Lifting-jack



T. A. (LAVENDER,

LIFTING JACK.

(No Model.)

Patented Jan. 20, 1891.

, head removed.

PATENT FFIGE THOMAS A. GAVENDER,

OF ST. LOUIS, MISSOURL LlFTlNG-J ACK.

SPECIFICATION forming part of Letters Patent No. 444,915, dated January .20, 1891.

Application filed July 8,1890.

T0 61/ whom, it may concern.-

Be it known that I, THOMAS A. CAVENDER, of the city of St. Louis, in the State of Misssouri, have invented a certain new and useful Improvement in LiftingJ-acks, of which the following is a full, clear, and exact description, reference being had to the accompan ying drawings, forming part of this specification.

This improvement belongs to that'class of jacks in which there is a rocking head carrying hinged pawls that alternately act upon ratchet-teeth at each side of the lifting-bar.

The novelties will be set forthin the claims.

Figure I is a side elevation of the jack with part of the hand-lever removed. Fig. II is an elevation at right angles to Fig. I. Fig. III is a detail side view with the side plate of the Fig. IV is a vertical section at IV IV, Fig. III. Fig. V is a side view of one of the pawls. Fig. VI isa horizontal section at VI VI, Fig. I. Fig. VIIis a horizontal section at VII VII, Fig. II. Fig. VIII is a detail of the forked end of the supplemental lever. Fig. IX is a perspective view of the dog which prevents the descent of the lifting-bar.

l is the base and 2 the uprights of the stand. The lifting-bar 3 plays between the uprights and has on its sides grooves 4: that receive guide-ribs 5 at the inner sides of the uprights, the lifting bar working on the guides. The upper end 6 of the lifting-bar may be simply flattened, as shown, or it may have a head of anyshape suited for the work for which it is intended.

7 are ratchet-racks upon the ungrooved sides of the lifting-bar. The lower end of the lifting-bar has a side projection 8, which may be inserted beneath any object to be lifted. The standards have bearingribs 9 rounded at top and which enter recesses 10 of similar shape in the under side of the rocking head 11, carrying the pawls so that the head rocks on these bearings. The head has a central orifice 12, through which passes the lifting bar and beside the lifting-bar the upward extension .2 of the uprights, the guide-ribs 5 extending to the tops of the extensions. The orifice 12 is extended at 12 upon each side, so as to allow the rocking of the head upon its bearings 9. The pawls 13 oscillate upon arbors or gudgeons having bearing in the Serial No. 357,636. (No model.)

head at 1t. 15 are fingers or extensions at one end of the pawls working in a recess 16 of the head closed by a side plate 17. The fingers 15 are connected by a spring 18, which forces the ends of the fingers away from each other and consequently forces the upper edges of the pawls 13 against the ratchetteeth 7. \Vhen, however, the lifting-bar is being lowered by the rocking of the head 11, it is necessary that the pawls should be automatically thrown out of engagement with the ratchets, which is done as they reach the lowest point. To accomplish this the central part 19 of the spring 18 extends upward and has an eye 20, which may be brought in line with a pin-hole 21, so that a pin 22 placed in the hole may pass through the eye 20 and thus interfere with the endwise movement of the spring, so that the spring has independent action on each pawl as the movement of one of the fingers 15 will not tend to move the other finger when the spring is locked in position by the pin 22. In this case when the head 11 is tilted a certain distance the lower pawl will be disengaged from the ratchet-tooth, being first drawn down from contact with and then thrown outward by the part of the spring 18 to which it is connected. At the same time the other pawl engages with one of the ratchet-teeth, and as the head 11 is rocked into the opposite position leaves its tooth, and so the lifting-bar is lowered a tooth at a time.

When the in 22 is not in use it ma T han on a chain 22, as seen in Figs. I and II. By way of explanation it will be said that when the spring 18 is not engaged by the pin 22 the lower pawl would be kept in engagement with the ratchet-tooth because its upper edge would be pushed toward the lifting-bar by the other pawl, as the latter would be forced outward at this time.

2-3 is a dog hanging from the uprights 2 on a pivot 2t when not in use. (See broken lines in Fig. I.) This dog may be swung up to engage, the ratchet, when desired, to pre vent the descent of the liftingbar, the dogin acting gravitating toward the ratchet.

The rocking head 1.1 has a socket 25, in which may be inserted a handle 26 by which the head is rocked. Provision is made for use of a supplementary handle or bar for rockin g the head by projections 27 on the sides die 26, a supplemental handle forked to embrace the rocking head, and projections on the rocking head engaging the fork, substantially as set forth.

of the head 1.1,behveen which projections are t l 1 i 3. The combination, in a lifting-jack, of

I i l l I passed the fingers 28 of the fork 29. The fork 29 has a socket 530 for the insertion of a handle similar to the handle 26.

5 I claim as my invention- 1. The combination, in a lifting-jack, of a lifting-bar with ratchet teeth on opposite sides, a rocking head having pawls engaging l the ratchets and having fingers 15, a spring 18, with projection 19, having eye 20, and pin 22, passing through the eye, substantially as and for the purpose set forth.

2. The combination, in a lifting-jack, of a lifting-bar 3, with ratehets 7, a rocking head IS with spring-pawls 13, and having afixed hanthe stand 1 2, with rounded bearings O, the head 11, rocking on these hearings and carrying spring-pawls 13, a lifting-bar having on opposite sides ratchet-s 7, engaged by the pawls, and a handle 26, adapted for rocking the pawl-head 11, substantially as set forth.

THOMAS A. CAVENDER.

Witnesses:

SAML. KNIGHT, J. M. MAROT. 

